Monday, July 6, 2009

Dark Matter/Energy, Resolution of Spacetime, etc.

Warning: This is wild speculation from someone who probably doesn't know what he's talking about. Please link me to any resources that would set me straight. :)

Cliffs Notes: Could the possibility of a fundamental resolution to the universe explain dark matter/energy?

Something about the search for the nature of dark matter/energy has always bugged me. Every time I've seen the topic explored (and I admit I haven't done any really advanced reading on it), they've taken for granted that the dark matter is a real substance that we can potentially interact with, and that the dark energy is an actual force being exerted on normal matter. In some ways it reminds me of the search for the luminiferous aether. Has anyone seriously explored the possibility that it's an effect of some (simpler) underlying cause?

In my time playing around with computer graphics, I became quite familiar with various aliasing effects. These range from "jaggies" and Moiré patterns in the spatial realm, to strobe effects like reversed wheel rotation in the temporal realm. These artifacts are distracting to viewers, so we use antialiasing techniques to alleviate the problem. Jagged edges are smoothed by what essentially amounts to blurring. Moiré patterns succumb to anisotropic filtering. Temporal antialiasing, aka motion blur, is more explicit about its goal. There is a fundamental limit to the amount of information an image can store at a particular resolution. Antialiasing removes a bit of certainty about the original source in exchange for a boost in perceived resolution.

What if there's a similar story going on "under the hood" of the cosmos? The first time I considered this was when I learned about Planck <measurement>. To my compsci-biased mind, this struck me as a fundamental resolution and bit-width/dynamic range for the universe. The first thing I noticed was that the blurring effect of antialiasing is roughly analogous to the uncertainty principle, which deals with effects on the Planck scale.

Obviously this is a retcon for me. I was simply trying to put the realities of QM into terms I could easily understand. But to my surprise, there are a few ideas being seriously advanced that are along the same lines:

The holographic and cellular automata explanations would certainly vindicate my resolution idea, and the fractal universe is at least compatible. When I heard about the holographic universe on The Skeptic's Guide to the Universe (#183), it made me think a bit (har) more about the bit-width or dynamic range analogy. They discussed how gravity wave detectors weren't seeing gravity waves but were getting a fairly consistent noise they weren't expecting (reminded me--and the cast--of the CMBR's discovery). This could easily be explained as a bottoming out of the dynamic range of the gravity field. Since gravity gets weaker as you get further from the source, the ideas above suggest that it would effectively disappear at some point.

Now dark energy attempts to explain why the universe's expansion is accelerating in defiance of gravity. What if there is basically no gravity at the massive distances between galaxies? That would at least explain gravity's impotence. Perhaps the extra oomph comes from quantum fluctuations (rounding error?) in this gravitational dead zone.

Dark matter tries to explain the opposite effect. Galaxies should be flying apart given the amount of matter we can detect inside them. What's holding them together? I haven't explored this idea in as much depth, but it seems like the resolution/dynamic range ideas could help explain this extra cohesiveness. Perhaps some of the resolution errors at the small scale create significant effects at the large scale. Maybe the dark energy effect is also "pushing" inwards over a large scale that isn't noticeable in the small scale.

Again, this is all wild speculation on my part. It's a fun exercise for my gray matter, but if it's all in vain, I'd rather turn my attention elsewhere. Let me know what you think.